Gold nanoparticles and radiofrequency in experimental models for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal and chemo-refractory cancers, clearly, alternative treatment strategies are needed. We utilized 10 nm gold nanoparticles as a scaffold to synthesize nanoconjugates bearing a targeting antibody (cetuximab, C225) and gemcitabine. Loading efficiency of gemcitabine on the gold nanoconjugates was 30%. Targeted gold nanoconjugates in combination with RF were selectively cytotoxic to EGFR expressing Hep3B and SNU449 cells when compared to isotype particles with/without RF (P < 0.05). In animal experiments, targeted gold nanoconjugates halted the growth of subcutaneous Hep3B xenografts in combination with RF exposure (P < 0.05). These xenografts also demonstrated increased apoptosis, necrosis and decreased proliferation compared to controls. Normal tissues were unharmed. We have demonstrated that non-invasive RF-induced hyperthermia when combined with targeted delivery of gemcitabine is more effective and safe at dosages ~ 275-fold lower than the current clinically-delivered systemic dose of gemcitabine

Mathematical modeling of starch oxidation by hydrogen peroxide in the presence of an iron catalyst complex

SSCI-VIDE+CDFA+ASOInternational audienceStarch oxidatio

Mathematical modeling of starch oxidation by hydrogen peroxide in the presence of an iron catalyst complex

SSCI-VIDE+CDFA+PTO:ASOInternational audienc

Carboxymethylation of cinnamylalcohol with dimethyl carbonate over the slag-based catalysts

The carboxymethylation of cinnamylalcohol with dimethyl carbonate was performed using low-cost catalysts obtained from desulfurization slag. Processing of steel slag performed by different techniques was resulted in a wide range of the catalysts with different morphological and structural properties. Catalytic evaluation of the slag catalysts illustrated diversity of the obtained results strongly dependent on the surface area, crystal morphology and basicity. Catalytic materials demonstrated high variability of the conversion (8–85%) exhibiting similar selectivity to the desired product – cinnamyl methyl carbonate (ca. 80%). A significant impact of ultrasonication on catalytic activity was observed. Comparison of the synthesized samples with commercial basic materials illustrated competitive ability of the slag catalysts. Based on the results of catalytic evaluation and product analysis the reaction network was proposed and verified by thermodynamic analysis. A kinetic model was developed to describe concentration dependencies in carboxymethylation

Application of microreactor technology to dehydration of bio-ethanol

Dehydration and etherification of bio-ethanol was studied in a microreactor using γ-alumina, H-Beta-38 and Sn-Beta-38 as catalysts. An extensive series of kinetic experiments was carried out in the microreactor device operating at ambient pressure and temperatures 225–325 °C. The H-Beta-38 catalyst coated microplates exhibited the highest production rate of ethene. While the fresh H-Beta-38 catalyst allowed complete conversion of ethanol and 98% selectivity towards ethene, the catalyst deactivated significantly with time-on-stream. Diethyl ether was the dominating co-product, whereas trace amounts of acetaldehyde were detected in the experiments. Based on the kinetic studies, thermodynamic analysis and catalyst characterization results obtained with SEM-EDX, TEM, nitrogen physisorption, FTIR-Pyridine and white light confocal microscopy, a surface reaction mechanism was proposed. The fundamental hypothesis of the reaction mechanism was the co-existence of two kinds of active sites on the catalyst surface, namely the Brønsted sites promoting dehydration and the Lewis sites responsible for etherification. The Brønsted sites deactivate, whereas the Lewis sites are more stable, which leads to a shift of the product distribution during long-term experiments, from ethene to diethyl ether. The rate equations were implemented in the microreactor model. The kinetic and adsorption parameters included in the model were estimated by non-linear regression analysis. The experimental data were satisfactorily described by the proposed mechanism. The work demonstrated that microreactors are strong tools in the determination of catalytic kinetics and catalyst durability

Glucose transformations over a mechanical mixture of ZnO and Ru/C catalysts: Product distribution, thermodynamics and kinetics

Transformations of glucose to 1,2-propylene glycol were studied over a mechanical mixture of ZnO and Ru/C catalysts in the presence of hydrogen. Different reaction conditions were evaluated by changing the reaction temperature and hydrogen pressure. In addition to the cascade mode of operation, also separate steps in the overall reaction network, such as hydrogenation of pyruvaldehyde and hydroxyacetone to 1,2-propylene glycol were investigated. Fructose as a starting material was also studied resulting in a propylene glycol yield of 37.5%. The optimal temperature for glucose transformation to propylene glycol was found to be 165 °C. The influence of temperature on the catalytic behavior was more prominent than the effect of hydrogen pressure. Thermodynamic analysis of glucose transformation to 1,2-propylene glycol was performed and a plausible kinetic model reflecting a complex reaction network was developed being able to describe the data in a reliable way

A new perspective on vegetable oil epoxidation modeling: Reaction and mass transfer in a liquid–liquid–solid system

A rigorous mathematical model was developed for a complex liquid–liquid–solid system in a batch reactor. The approach is general but well applicable for the indirect epoxidation of vegetable oils according to the concept of Nikolaj Prileschajew, implying in situ prepared percarboxylic acids as epoxidation agents. The model considers intra- and interfacial mass transfer effects coupled to reaction kinetics. The liquid phases were described with chemical approach (aqueous phase) and a reaction–diffusion approach (oil phase). The oil droplets were treated as rigid spheres, in which the overall reaction rate is influenced by chemical reactions and molecular diffusion. The model was tested with a generic example, where two reactions proceeded simultaneously in the aqueous and oil phases. The example (i.e., fatty acid epoxidation) illustrated the power of real multiphase model in epoxidation processes. The proposed modeling concept can be used for optimization purposes for applications, which comprise a complex water–oil–solid catalyst system

Cytotoxicity and variant cellular internalization behavior of water-soluble sulfonated nanographene sheets in liver cancer cells

Highly exfoliated sulfonated graphene sheets (SGSs), an alternative to graphene oxide and graphene derivatives, were synthesized, characterized, and applied to liver cancer cells in vitro. Cytotoxicity profiles were obtained using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, WST-1[2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, and lactate dehydrogenase release colorimetric assays. These particles were found to be non-toxic across the concentration range of 0.1 to 10 μg/ml. Internalization of SGSs was also studied by means of optical and electron microscopy. Although not conclusive, high-resolution transmission and scanning electron microscopy revealed variant internalization behaviors where some of the SGS became folded and compartmentalized into tight bundles within cellular organelles. The ability for liver cancer cells to internalize, fold, and compartmentalize graphene structures is a phenomenon not previously documented for graphene cell biology and should be further investigated

Kinetic and Thermodynamic Analysis of Guaiacol Hydrodeoxygenation

Abstract: Kinetics of guaiacol hydrodeoxygenation (HDO) was studied using supported MoxC–SBA-15 and as a comparison 5 wt% Pt/C under 30 bar hydrogen at 200 °C and 300 °C. Catalyst characterization was done by a range of physical methods including also determination of the amount of coke and the nature of adsorbed species. Pt/C gave 2-methoxycyclohexanol as the main product, whereas Mo2C–SBA-15 promoted direct deoxygenation exhibiting also strong adsorption of guaiacol on the catalyst surface and formation of oligomers. Thermodynamics of guaiacol HDO was elucidated and the reaction network was proposed based on which kinetic modelling was done. Graphic Abstract: [Figure not available: see fulltext.

A New Imaging Platform for Visualizing Biological Effects of Non-Invasive Radiofrequency Electric-Field Cancer Hyperthermia

Herein, we present a novel imaging platform to study the biological effects of non-invasive radiofrequency (RF) electric field cancer hyperthermia. This system allows for real-time in vivointravital microscopy (IVM) imaging of radiofrequency-induced biological alterations such as changes in vessel structure and drug perfusion. Our results indicate that the IVM system is able to handle exposure to high-power electric-fields without inducing significant hardware damage or imaging artifacts. Furthermore, short durations of low-power (< 200 W) radiofrequency exposure increased transport and perfusion of fluorescent tracers into the tumors at temperatures below 41°C. Vessel deformations and blood coagulation were seen for tumor temperatures around 44°C. These results highlight the use of our integrated IVM-RF imaging platform as a powerful new tool to visualize the dynamics and interplay between radiofrequency energy and biological tissues, organs, and tumors